Underground Infrastructure - November 2023 - 20

DAMAGE PREVENTION& SAFETY
SUE, Vac Excavation Increase
Safety and Save Time
When it comes to underground utilities, safety is paramount.
As municipalities grow and various areas undergo advancement
and development, the number of buried utilities grows.
Likewise, the number of potential problem points grows, including
more live and abandoned utilities interfering with
new projects.
Subsurface Utility Engineering, or SUE, looks to counteract
these pain points or at least decrease them through civil
engineering, surveying and vacuum excavation. Greg Jeffries is
the chair of the Subsurface Utility Engineering & Investigative
Committee at the American Society of Civil Engineers Utility
Engineering and Surveying Institute (ASCE/UESI).
" SUE, to me, is the proper characterization of existing
utilities and avoidance of utility conflicts, " said Jeffries. " Primarily
SUE should be integrated in the early design process
to give the design people the best foot forward. The idea is to
give them very valid, precise information. "
In years past, SUE happened far into the process. It was a
matter of finding out how bad an underground obstacle was
rather than being used early in the design phase to help avoid
surprises. SUE now considers not only utilities but also underground
vaults and manholes to give a full picture look at
what is occurring in that underground space and show existing
structures.
Reducing risk
For example, in Tampa, Fla., when a 72-inch drainage trunk
line was going to be put under an old cobblestone street, the
underground structures in addition to the utilities caused issues.
SUE showed the pipe wouldn't work there, and the project
would have been better served had SUE been utilized in
the design stage.
" SUE as a whole isn't about eliminating risk such as encountering
utility issues, but rather it's about drastically lowering
the risk profile, " said Jeffries. " There's a precision design when
SUE is used, and it's a buildable design. "
The vast majority of contracts put responsibility on the
contractor to confirm all utilities. That puts every construction
dollar at risk because there isn't good subsurface information.
" All construction projects cost roughly 14 percent more
than they should cost because of these unmitigated risk profiles
that are being dealt with on the contractor side of the
equation, " said Jeffries.
It's not only a matter of cost and dealing with problems in
the build phase rather than the design phase. It's also a matter
of safety. Digging into a utility creates a large safety risk. This
is especially the case when working around natural gas lines.
" Safety is definitely the big consideration in SUE. It's no
question, " said Jeffries. " The more information we know about
the utility installations that are out there, the more we can avoid
an unnecessary or unwanted interaction with that utility. "
That is one major reason why vacuum excavation is helpful
when it comes to SUE. Rather than using a shovel or backhoe
to find out what lays beneath the surface, vacuum excavators
use compressed air or pressurized water to uncover underground
utilities. That loose soil is then vacuumed out of the
way into a debris tank. This helps avoid any contact with utili20
NOVEMBER 2023 | UndergroundInfrastructure.com
http://www.UndergroundInfrastructure.com
Underground Infrastructure - November 2023

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